Directionally stable self propelled vehicle

ABSTRACT

A directionally stable self propelled vehicle movable in any desired direction and equipped with at least two front and two rear rotatable driving gears having ground contact elements mounted obliquely to the axes of rotation of the driving gears. The ground contact elements being mounted so that the ground contact lines for the front set of driving gears intersect in the backward direction and that the ground contact lines for the rear set of driving gears intersect in the forward direction.

United States Patent [1011 1 51 July 17, 1973 [54] DIRECTIONALLY STABLESELF 2,154,191 4 1939 Welsh 180/7 A PROPELLED VEHICLE 2,495,643 1/1950115/19 X [76] Inventor: Bengt Erland Ilon, St m a vag n 3,420,326 l/1969Kusmer 180/6.2

S461 38 Emma Swede FOREIGN PATENTS OR APPLlCATlONS [221 Flledi 19711,153,266 8/1963 Germany 180/7 A App]. No.2 204,129

[] Foreign Application Priority Data Dec. 14, 1970 Sweden 16864/' [52]11.8. C1. ISO/6.2, /1 R, 115/19, /7 A, 301/5 PR [51] Int. Cl B62d 11/00[58] Field of Search ISO/6.2, 3 A, 7 A, 180/7 R; 115/1 R, 19; 305/52;301/5 PR [56] References Cited UNITED STATES PATENTS 3,396,690 8/1968Tsunazawa 180/6.2 X

3,591,241 7/1971 Allen 180/7 R 669,210 3/1901 Burch 180/7 A 1,672,6136/1928 Howell 115/19 Primary Examiner-Benjamin Hersh AssistantExaminer-John A. Pekar Attorney-John J. Dennemeyer [57] ABSTRACT tion.

5 Claims, 17 Drawing Figures 24 2e 31 31 l-23 21 i Pu s f c a c, B c B ca c .a c a t Fig. 11d Fig.11b Fig.11c c Fig.11d Pd Fidjie, Fig.11f PfFig.11g p A 0' A 0 A o A o A D A D A o.

Patented July 17, 1973 3 Sheets-Sheet 2 Patented July 17, 1973 3Sheets-Sheet I5 Q E 2 3 u m E E u E L Q m U m E u: o m

Q i E u m U E m m D E U m DIRECTIONALLY STABLE SELF PROPELLED VEHICLEThe present invention relates to a directionally stable self propelledvehicle and more precisely a directionally stable self propelled vehiclecapableof movement in any desired direction over land or other surfacesand fitted with at least two front and two rear rotatable assemblies orsets of driving gears positioned about the longitudinal vertical sectionthrough the vehicle and with these working in conjunction with grippinggear or ground contact elements mounted obliquely to the axes ofrotation of the driving gear. Such vehicles could be used under a widerange of conditions, e.g. as dry land vehicles, climbing vehicles,amphibians and combined snow, ice and water vehicles.

Vehicles of this kind have previously been suggested for use, forexample, over snow and ice covered ground. In one form of this type ofvehicle the driving gear consists of coil shaped drums. These are fittedexternally with screwthread like gripping gear or ground contactelements and are arranged in pairs on axles parallel to the longitudinalaxis of the vehicle with each pair driven by a common motor. The axlesare arranged to rotate in opposite directions and propulsion of thevehicle is by means of the gripping gear which, on the drums of oneaxle, is threaded in one direction and which, on the other drums, arethreaded in the other direction. For steering, the vehicle is fittedwith a steering wheel which, through gearing, operates'movable steeringrunner assemblies in the front of the front of the vehicle. In spite ofthis steering arrangement the vehicle is not completely directionallystable. It friction between the drums and the surface varies, so that itis not equal for all drums, the rear end 'of the vehicle swings sidewaysin one direction or the other which, under some circumstances, caninvolve considerable risk. Vehicles of this type also suffer from thedisadvantage that they are rather long and difficult to maneuver in thatthe steering is by means of runners. The turning radius of the vehicleis thus relatively great which, especially in difficult terrain,constitutes a further serious drawback. This steering arrangement isthus a limiting factor both for this reason and for many others worthyof consideration in view of the possible range of uses for the vehicle.

By means of the teaching of this invention, the above drawbacks arecompletely avoided.

It is an object of the invention to provide a vehicle which iscompletely stable directionally and which is easily maneuverable as wellas freely capable of movement in any desired direction which, in use,enables the turning circle to be as small as necessary and even, ifrequired, to be virtually zero.

In accordance with the invention the driving gears are individuallyrotatable and are obliquely mounted by the ground contact elements insuch a way that the ground contact lines for the front sets of drivinggear intersect in the backward direction and that the ground contactlines for the rear sets of driving gear intersect in the forwarddirection. I

The attached sketches show schematically a number of details of theinvention. Of these:

FIG. 1 is a horizontal projection of a vehicle incorporating theinvention, seen from below;

FIG. 2 is a side view of the vehicle of FIG. 1;

FIG. 3 is an end view of one of the vehicles sets of driving gear;

FIG. 4 shows a detailed view of one variant of such driving gear;

FIG. 5 shows a detailed view of another variant of the driving gear;

FIG. 6 shows a detail of the variant of FIG. 5 to a larger scale;

FIG. 7 is a longitudinal section of another vehicle incorporating theinvention; I

FIG. 8 is a horizontal section of the vehicle of FIG. 7 seen from below;

FIG. '9 is a detailed view of one set of driving gear of the vehicle ofFIG. 8;

FIG. 10 is a horizontal projection of the driving gear of FIG. 9;

FIGS. lla 1 lg show a'number of possible movement combinations for thevehicle of FIGS. 7 and 8.

The vehicle to the design shown in FIGS. 1 and 2, which is seenprimarily as being suitable for snow and ice covered ground, is fittedwith driving gear in the form of two front and two rear longitudinalcylindrical rollers, 1 and 2 respectively. The rollers which, with theiraxles, are oriented parallel to the longitudinal axis of the vehiclesvertical mid-section and are arranged in pairs about this section, beingindependently rotatable within the yoke shaped supports 3, 4 which, bymeans of transverse axles 5, 6'and links 7, act as suspension for thevehicle body 8. This also carries a driving motor 9 from which thedriving torque, by meansof hydraulic couplings l0 of known d'esign,istransmitted partly directly to the forward driving gear I and partlyindirectly by the central through axle 11 to the rear driving gear 2.Each of the sets of driving gear is fitted with oblique screw threadshaped strips 12 which form groups of driving or ground contact elementswith a pitch angle such that the lines of contact with the ground l3, 14for the forward driving gear converge towards the rear while the linesof contact with the ground 15, 16 for the rear driving gear converge inthe forward direction. This arrangement of the directions of the groundcontact lines is of decisive importance to the directional stability ofthe vehicle. A change in the course of the vehicle involves all theground contact elements being able to turn about a common centre ofrotation. If itis assumed, for the sake of simplicity, that just oneground contact element on each set of driving gear is in contact withthe ground, it can be seen that the centre of rotation for both sets offront driving gear, represented by the pointof intcrsectio'n of thenormals to the elements in contact with the ground, cannot coincide withthe corresponding centre of rotation for the contact elements of the twosets of rear driving gear since the directions of the contact lines aresuch that those I3, 14 for the front driving gear converge to the pointsof intersection cannot coincide. Thus, if the friction between thedriving gear and the ground shouldvary as mentioned above, the vehiclewill maintain its course. This situation does not however hinder themaneuvering of thevehicle in other directions. Deliberate changes in thedirection of movement 'of the vehicle may be achieved by regulating thespeed and/or the direction of rotation of the individual sets of drivinggear,

and the vehicle may thus be moved in any desired direction as describedbelow.

Forward movement in a straight line, i.e. in the direction of the arrowA in FIG. 1, is obtained if all sets of driving gear are driven by themotor 9 through the hydraulic couplings 10 at the same speed, providedof course that the pitch and diameter of the ground contact elements areequal for all sets of driving gear, and

if the direction of rotation of the sets of driving gear, takencyclically, are alternate, which implies that any two adjacent sets ofdriving gear rotate in opposite directions. Backward movement in astraight line is obtained in a similar way, the direction of rotation ofall sets of driving gear being reversed. Sideways movement in a straightline, i.e at right angles to the arrow A, is obtained by rotating alldriving gear in one and the same direction. It is obvious that byaltering the speed of rotation of part of the driving gear with respectto that of the remainder, the vehicle can also be made to follow anarbitrarily straight or crooked path.

As will be seen from the above, the movement of the vehicle in thedesired direction requires the sets of driving gear to be mountedseparately and so arranged that they can be rotated independently inboth speed and direction. It is thus also possible to rotate the vehicleabout its own central vertical axis. This, may be achieved by makingboth sets of forward driving gear l rotate in one and the same directionwhile both rear sets of driving gear 2 rotate in the opposite direction.The driving gear blades could, as shown in FIG. 4, be fitted with smallwheels or rollers 16 mounted in the outer edge of the blade, assuringthat their axes of rotation are at least approximately at right anglesto the line of the blade. This would facilitate the use of the vehicleover rough ground, i.e. surfaces other than snow and ice. Alternatively,as shown in FIG. 5, the same end may be achieved by mounting rotatingsegments or similar elements 17 in the peripheral groove. By suchmeans'the friction between the driving gear and the ground can bereduced. Element 17 could, as shown in FIG. 6, be made in the form ofswinging arm assemblies 19 mounted on individual axles l8 and having endsurfaces 20 suitable for contact with the ground.

The vehicle of the design shown in FIGS. 7 and 8, envisaged for use oncomparatively even surfaces, is equipped with two front driving wheels21 arranged in a pair along the transverse axis of the vehicle andcoaxial axles 23 lead from a forward gearbox 22 to the front drivingwheels 21. Two rear driving wheels 24 are similarly arranged along thetransverse axis of the vehicle, and coaxial axles 26 lead from a reargearbox 25 to the wheels 24. Both gearboxes 22, 25, which are arrangedso as to allow selection of the desired speed and/or direction ofrotation of the driving wheels, are in turn, by means of their ownlongitudinal axles 27, 28, connected to the ordinary gearbox 30associated with the driving motor 29 of the vehicle as shown in FIG. 7which is a section along the line VII VII in FIG. 8. Each of the drivingwheels is equipped on its periphery with a number of rotatable sheavesor wheels 31 which are mounted obliquely so as to make an angle ofapproximately 45 with the plane of the wheel and so that the directionof the ground contact lines 32, 33 for the sheaves on the front drivingwheels 21 converge to the rear while the ground contact lines 34, 35 forthe sheaves on the rear driving wheels 24 converge in the forwarddirection. The driving wheels are also independently mounted and arecapable of individual regulation with regard to speed and direction ofrotation by means of the gearboxes 22, 25, 30 so that the vehicle can bemade to move in a directionally stable manner both forwards andbackwards as well as sideways and in intermediate directions as shown inFIGS. 1 la 1 lg. The vehicle shown in FIG. 7 can move in any desireddirection. 7

For the vehicles depicted symbolically in FIGS. lla 11g, shown inhorizontal projection from above, the four driving wheels are designatedA, B, C, D and their directions of rotation are shown by means of arrowson each wheel. Thus in FIG. 11a all the driving wheels rotate in thesame direction and the vehicle is made to move in the direction of thearrow Pa. This means that the sheaves round the periphery of the drivingwheels are brought in sequence into contact with the ground withoutrotating about their own axes. It is clear that if the direction of therotation of all the driving wheels is reversed the vehicle will move inthe direction opposite to that of the errow Pa, i.e. backwards. Forspecial purposes the direction of rotation of wheels A and D can be madeopposite to that of wheels B and C, namely if it is required to producea shortening or lengthening of the wheelbase. The arrangement must thenbe such that it permits a mutual displacement between wheels A and D onthe'one part and wheels B and C on the other. A change in the directionof rotation of wheels B and C in FIG. 11a should thus involvedisplacement of wheels A and D towards B and C, and a change in thedirection of rotation of wheels A and D should involve a displacement ofthese wheels away from wheels D an C. Such an arrangement can beparticularly useful in, for example, casualty transport applications.The track widths for the front and rear wheels can with advantage bemade unequal so that a shortening of the wheelbase is facilitated andthe wheelbase can thus be made as short as possible.

If the driving wheels A and C, as shown in FIG. 11b, rotate in onedirection while wheels B and D rotate in the opposite direction, thevehicle moves sideways as shown by the arrow Pb and, on all wheels, thesheaves in contact with the groundwill rotate about their own axes insuch a way that the ground contact points move in paths parallel to thearrow Pb. In this case also it is clear that if the direction ofrotation of all wheels is reversed, the vehicle moves in a directionopposite to that of the arrow Pb.

Ifthe driving wheels B and D rotate in opposite directions while wheelsA and C are held stationary, the vehicle moves diagonally in thedirection of the arrow Pc as shown in FIG. llc. On wheels A and C thesheaves in contact with the ground rotate about their own axes and theirground contact points move in paths parallel to the arrow Pc. This alsoapplies to wheels Band D. In this case also, of course, if the directionof rotation of wheels B and D is reversed while wheels A and C are heldstationary, the vehicle moves in a direction opposite to that of thearrow Pc. Similarly movement in the other diagonal directions may beachieved by movement of wheels A and C.

If, as shown in FIG. 1 1d, wheels A and B rotate in one and the samedirection while wheels C and D rotate in the other direction, thevehicle will turn on the spot as indicated by the arrow Pd. In this caseall the sheaves in contact with the ground will rotate about their ownaxes. If the direction of rotation of all wheels is reversed the vehiclewill of course rotate in the direction opposite to that indicated by thearrow Pd.

If, as shown in FIG. lle, wheels A and B rotate in one and the samedirection while wheels C and D are held stationary or made to rotate ina similar direction but 5 with a speed differing from that of wheels Aand B, the vehicle will move along a curved path as shown by the arrowPc and with a curvature depending on the difference in the speed ofrotation of wheels A and B on the one part and wheels C and D on theother.

If, as shown in FIG. 11f, wheels B and C rotate in opposite directionswhile wheels A and D are held stationary, the vehicle moves in thedirection of the arrow Pf, moving the front of the vehicle sideways,i.e. giving a rotation about the point of intersection of the normals 1to the sheaves forming the points of contact with the ground for wheelsA and D. Similarly the vehicle moves in the direction of the arrow Pg asshown in FIG. llg if wheels A and D rotate in opposite directions whilewheels B and C are held stationary.

In the case of movement as shown in FIGS. lle 1 1g the sheaves incontact with the ground rotate about their own axes in one direction oranother which means that the rolling resistance is relatively low inthese cases.

From the above it follows that the vehicle incorporating the inventionis arbitrarily movable in all possible directions and that all movementsof the vehicle take place without scraping or sliding on the ground.

As shown in FIGS. 9 and 10, the sheaves or wheels 31 could be replacedby rollers 36 which could with advantage be made convex or bobbinshaped. Such rollers could be made to overlap one another more easilythan sheaves and thus give a smoother motion with both reduced vibrationand a lower point loading on the 35 ground. Of course, as analternative, screw thread shaped elements of the kind shown in FIGS. 5and 6, or a similar design with a pitch angle corresponding to theobliquity of the sheaves 31, could be employed.

The above forms of the arrangement invented could be modified in one ormore respects within the framework of the concept of the invention. Forexample the vehicle could, if required, be fitted with more than foursets of driving gear and the driving gear could be fitted withindividual motors of one kind or another, capable of independentregulation. In this connection the concept vehicle ought to be taken inthe broadest interpretation and it should thus be regarded as alsoencompassing other types of transport vehicle.

What is claimed is:

1. A directionally stable self-propelled vehicle adapted for travel inany desired direction over land or other surfaces, said vehiclecomprising, in combination:

a. a first pair of axles secured to the forward portion of the vehicleand extending transversely outwardly with respect to the longitudinalaxis of the vehicle,

b. a second pair of axles secured to the rearward portion of the vehicleand extending transversely outwardly with respect to the longitudinalaxis of the vehicle,

c. a pair of driving means secured to the outer ends of both the firstand second pair of axles wherein each driving means is independentlyrotatable by its associated axle and includes: l. a driving wheel, and

2. a plurality of bobbin-shaped rollers secured to the periphery of thedriving wheel at an angular disposition with respect to the axis ofrotation of the wheel such that the rolling direction surface contactlines of the rollers of the front wheels intersect at a point rearwardof said first pair of axles while the rolling direction surface contactlines of the rollers of the rear wheels intersect at a point forward ofsaid second pair of axles.

2. The vehicle of claim 1 wherein both the front and rear rollingdirection surface contact lines form an angle of from 30 to 60 withrespect to the axis of rotation of the wheels.

3. The vehicle of claim 2 wherein the angle is 45.

4. The vehicle of claim 1 further including first and second motorsdrivingly connected to the first and second pair of axles, respectively,for independentlyrotating each of the axles. I

5. The vehicle of claim 1 wherein the rolling direc tion contact linesof the rollers are each parallel to the longitudinal axes of the rollersfrom which each line is determined.

1. A directionally stable self-propelled vehicle adapted for travel inany desired direction over land or other surfaces, said vehiclecomprising, in combination: a. a first pair of axles secured to theforward portion of the vehicle and extending transversely outwardly withrespect to the longitudinal axis of the vehicle, b. a second pair ofaxles secured to the rearward portion of the vehicle and extendingtransversely outwardly with respect to the longitudinal axis of thevehicle, c. a pair of driving means secured to the outer ends of boththe first and second pair of axles wherein each driving means isindependently rotatable by its associated axle and includes:
 1. adriving wheel, and
 2. a plurality of bobbin-shaped rollers secured tothe periphery of the driving wheel at an angular disposition withrespect to the axis of rotation of the wheel such that the rollingdirection surface contact lines of the rollers of the front wheelsintersect at a point rearward of said first pair of axles while therolling direction surface contact lines of the rollers of the rearwheels intersect at a point forward of said second pair of axles.
 2. aplurality of bobbin-shaped rollers secured to the periphery of thedriving wheel at an angular disposition with respect to the axis ofrotation of the wheel such that the rolling direction surface contactlines of the rollers of the front wheels intersect at a point rearwardof said first pair of axles while the rolling direction surface contactlines of the rollers of the rear wheels intersect at a point forward ofsaid second pair of axles.
 2. The vehicle of claim 1 wherein both thefront and rear rolling direction surface contact lines form an angle offrom 30* to 60* with respect to the axis of rotation of the wheels. 3.The vehicle of claim 2 wherein the angle is 45*.
 4. The vehicle of claim1 further including first and second motors drivingly connected to thefirst and second pair of axles, respectively, for independently rotatingeach of the axles.
 5. The vehicle of claim 1 wherein the rollingdirection contact lines of the rollers are each parallel to thelongitudinal axes of the rollers from which each line is determined.